1. Field of the Invention
The present invention relates to a waterproof structure of a respiratory tube, and more particularly, relates to a waterproof structure of a respiratory tube used for snorkeling.
2. Descriptions of the Related Art
Respiratory tubes are essential for snorkeling. Even a beginner who cannot swim can snorkel if he or she knows how to use the respiratory tube. For this reason, manufacturers have continuously improved respiratory tubes to make them more convenient and easier to use.
The most important component of the respiratory tube is its waterproof structure. In a conventional waterproof structure, which is disposed at the end of the respiratory tube, there is a floating ball therein that functions much like an air floating bucket. When the respiratory tube is immersed into water, the floating ball will float upwards and seal the respiratory tube with the aid of a properly designed connecting rod that is connected with the floating ball. Sea water then is prevented from entering, allowing the diver to dive into the sea.
In addition, a conventional respiratory tube having a waterproof valve is disclosed in U.S. Pat. Nos. 7,077,127 and 6,904,910. The waterproof valve of the respiratory tube comprises a soft diaphragm disposed at a top opening of the respiratory tube by a linkage. When a floating device of the respiratory tube is immersed into water, it will drive the linkage to indirectly move the diaphragm against the opening of the respiratory tube thereby preventing water entry. On the contrary, when the floating device of the respiratory tube departs from water, it will drive the linkage to indirectly move the diaphragm apart the opening.
Unfortunately, this conventional waterproof structure requires a complex assembly process and increases the manufacturing cost because of the relatively large number of components. Furthermore, when using the conventional respiratory tube, sometimes the waterproof structure closes prematurely even before the diver dives into the water, or is prone to water entry, thus preventing the respiratory tube from functioning properly.
Therefore, it is important to design a simplified waterproof structure that can function properly at all times without it being too costly.